Implement BeamWeapon

[Trigary]

Implement the BeamWeapon weapon system. All you need is some Unity experience: you can copy the LaserWeapon's implementation with one modification: instead of selecting a single RealLiveBlock with the raycasting, select multiple.

This is the description of the beam weapon:

A hitscan weapon which fires a laser beam.
If a block was hit, all blocks behind it are also damaged until the shot has run out of damage to deal.
Damage can only be dealt to a single structure by each shot.

[maximetinu]

I'll do it!